“Slayin” is an app that wears its retro gaming heart on its sleeve. You don’t have to look hard to spot its influences from games like “Castlevania,” “Ghosts and Goblins,” “Metal Slug,” “Mega Man,” and more, yet “Slayin” is also unique. It touts its gameplay as the first endless action RPG, in that you are constantly moving, constantly battling, and constantly trying to level up and improve yourself through statistical upgrades and better equipment.

Mix those notions of nostalgic ideology and brand new mobile gameplay together, and it’s like tasting peanut butter and chocolate together for the first time. Yes, “Slayin” is basically the Reeses of the app world, yet infinitely more filling.

“Slayin” tasks you with choosing between three character classes (the strong knight, the ability loaded wizard, and the dual sword wielding knave) and embarking on a timeless quest to slay a dragon, and all other minions and bosses along the way. While all the classes have their own unique abilities and progression systems, they are all bound to the very simple play style which has you constantly moving in a small area, and shifting your direction left and right as you work to destroy everything in your path.

It may be simple, but it works so, so well. “Slayin” refers to itself as the first of its kind, and its uniquely relentless and dangerously addictive style certainly feels the part. Once you quickly adapt to the flow of “Slayin,” you’ll find yourself in that great zen like state a game can provide, where your actions seem to occur a fraction of a second before you even think them. You’ll need those extra quick reactions, as “Slayin” borrows its difficulty from many of those titles that influenced it, though I’m happy to report that the challenge is one based of skill over trial and error for the most part.

While more of an action game than an RPG, those role playing elements still shine in “Slayin,” especially when it comes to its upgrade system. As mentioned, each character type has their own upgrades and equipment available, which the game cleverly lets you purchase without much break in the action courtesy of an appearing shop keeper. Thankfully, the vast majority of your purchases are made with in-game currency, and the additional in-app purchases available are mostly novelty items that in no way are necessary for your completion, or enjoyment, of the game.

Where “Slayin” really hits it out of the park, though, is in that retro style. Apply this concept to any other form, and it just wouldn’t have worked as well as it does here in a hybrid world of 8 and 16 bit video game design. There isn’t a visual or audio element that doesn’t harken back to that time, and yet “Slayin” also adds just enough of its own style to those elements to feel fresh. This is particularly evident in the music (done by one of the same guys who did “Retro City Rampage”) where a few notes will remind you of certain classic games, yet the score itself is more of a unique entrant into the field than a mere tribute.

There are games out there without a fraction of the addictive nature and charm of “Slayin” that are still great. “Slayin” is a title that focuses on the advantages of the mobile platform, and uses every single one of them to craft an experience that is a feast for the eyes, ears, mind, and hands. It’s a twitch based actioner with equal measures of looks and heart, as well as a surprising amount of depth.

If you ever want to see and experience the design pinnacle of a three button game, then you need “Slayin.” As I type this, I just want to jump back into it’s one more play world that inevitably stretches on for hours, so let me wrap this up quickly by crowning “Slayin” the unquestioned app of the week.